Preparation of methylol compounds of urea or thiourea stable in storage



Patent Nap, 3, 12

" wrap j PAT N FFlCE v I 2,300,976 a rasmasrrou or METHYLOL conrormns FUREA STCDRAGE 0R THIOUBEA STABLE IN -Hans' Scheuermann, Ludwigshalen onthe Rhine, Germany; vested in the Allen Property Custodian l No Drawing.Application June 25, 1939, Serial No. 280,570. InGermany 12, 1938 4Claims. (01. zes -1i The present invention relates to improvements inthe preparation of methylol compounds .of urea or thiourea which arestable in "storage.

Solutions or methylol compounds of urea or thiourea or both, such asareobtained for example by dissolving urea orthiourea or both,

for example at 45 .G. .and at a pH value 01 8.0

' in from 30 to 40 per cent aqueousformaldehyde,

do not have unlimited stability.- On the contrary there separatetherefrom upon cooling, after a shorter or longer time, solid compoundsso that the solutionssolidify to a pulp. It the solutions be stirredduring the separation of the solid compounds, a salve-like pasteisobtained.

This paste has a somewhat better stability in storage and may be keptforexample for some weeks. After this. time, howeveiyit can no Example 11050 parts of urea are dissolved in 3500 parts of 30 per cent aqueousformaldehyde solution at 45 C.-and a pH value of 8.2. After half an hourthere are added, also at 45 0., 84 parts of a. hydroxycelluloseglycollic acid. either andvth e mixturejs allowed to become cold whilestirring. The paste thus obtained may if] desired be passed throughaficolloid mill or a color mill to produce ,6. fine dispersion. Afterstorage for six months,

I it will still dissolve inwarm water to give a longer be used, butsolidifies to a more or less solid cake. This cake. even when it isfinely divided, can no longer be satisfactorily brought into solution.

.I have now found that dispersions, that is solutions or suspensions ofthe said. methyol comstorage by adding thereto awatersoluble practicallyneutral highly polymeric thickening agent. for this purpose all inertsubstances, 1. e. substances which do-not combine or react with themethylol compounds to i'orin insoluble compounds as for example caseinor albumens do'are suitable. For' example there may be mentionedwatersoluble cellulose esters or others. and also cellulose etherderivatives containing 'carboxyl clear solution.

Example 2 added at 45 C. and ata pH value of 8.2 to a so-, lution of 144parts of a percent solution of.

polymethacrylic acid soduim salt in 3000 parts of per cent aqueousformaldehyde solution.

After half an hour, the solution is allowed to become cold whilestirring well. A paste is obtained which can be stored very well.

, after storage forseveral months it still dissolves .Pounds can berendered of very good stability in readily in warm water and may be usedfor ex- 251 ample for improving fibrous materials.

groups, which are obtainable by etherifyingcellulose withhydroxycarboxylic acids, and their salts, and watersoluble polyvinylcompounds, such aspolymetliyl-vinyl ether or alkali salts of polyacrylicacids. Watersoluble derivatives of partially degraded cellulose, as forexample hydroxycellulose glycollic acid, are also suitable. Generallyspeaking, the desired action is obtained by the addition of from aboutto about smaller or larger amounts can also be employed. The capacity ofthe pastes ior-being stored is excellent. The particles do'notconglomerate and the products" will dissolve in warm water even afterseveral months.

,'I'he following examples will, further illustrate how thisinventionfmay be carried out in pracexamples; The parts are by weight.

. 50 tice but theinvention is not restricted to these ,5 per cent of thesaid thickening agents, but

What I claim is:

temperature of about 45 C. and a pH of about ,8, awater-solublepractically neutral colloidal substance inert against said methylolcompounds in an amount sufiicient to thicken the pasty mass and water inan amount insufllcient to dissolve" both said methylol compounds andsaid colloidal substance together. 3

2. The composition as defined in claim 1, wherein said water-soluble.practically neutral colloidal substance is polymethacrylic acid so-Qdium salt. e l

.3. The composition as defined; in claim 1, wherein said water-solublepractically l neutral colloidal substance is'a water soluble cellulosevether; l A 4. The composition as defined in claim 1,

' wherein said water-soluble practically neutral colloidal substance ishydroxy-cellulcse ulycolic acid ether. I

i HANS SCBEUERMANN.

600 parts of urea and 380 parts of thiourea are wad-se

